In an arc furnace, in particular, a three-phase arc furnace, there has been the problem that the metal material in the furnace is not melted uniformly. That is, while melting of the metal material quickly advances in the hot spot near each of the three electrodes, the metal material tends to remain unmelted in the cold spot distant from each of the electrodes. Therefore, there have been the problems that electric power more than necessary to melt the metal material in the cold spots is required, and that the furnace wall lining is damaged due to excessive supply of electric power in the hot spot. Consequently, Patent Document 1 proposes the arc furnace that enables uniform melting by making a bottomed cylindrical furnace body rotatable around a cylinder axis thereof, and replacing the hot spots and the cold spots.
[Patent Document 1] JP-A-S60-122886